Patent Application
20090051475
This Non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 096131435 filed in Taiwan, Republic of China on Aug. 24, 2007, the entire contents of which are hereby incorporated by reference.
1. Field of Invention
The invention relates to an embedded inductor and the manufacturing thereof.
2. Related Art
In the development of electronic products, basic and important elements such as inductors play very important roles. Therefore, how to make high-quality inductors is one goal of the field. In view of the miniaturization trend, embedded inductors are introduced.
The production method for a conventional embedded inductor is mostly dry processes. Magnetic powder and resin are mixed in a dry way before they are molded by thermal compression. Since there insufficient adhesive force between them, the resin often cannot be uniformly distributed on the magnetic powder surface during the stirring process. The inductance and performance (e.g., induced charge) of the conventional inductor may be affected due to cracks in the subsequent resin curing process. Besides, the resin curing process requires a larger molding pressure. This increases electrical power use and reduces the lifetime of molding tools. These drawbacks call for improvements in conventional inductors.
Therefore, it is an important subject to provide an inductor and a manufacturing method thereof that can fully mix the magnetic material and resin.
In view of the foregoing, the invention is to provide an embedded inductor and the manufacturing method thereof that can fully mix the magnetic material and resin to ensure the stability in the inductance and performance. In addition, the manufacturing method of the inductor of the invention does not require a high molding pressure and thus can elongate the lifetime of molding tools.
To achieve the above, the invention discloses a manufacturing method of an embedded inductor. The method includes the steps of: performing an insulation process for a magnetic powder to obtain an insulated magnetic powder; performing a surface process on the insulated magnetic powder; mixing the surface-processed insulated magnetic powder with a liquid resin to form a mixture; providing a coil; covering the coil with the mixture; and performing pressing and curing processes to obtain the embedded inductor.
To achieve the above, the invention also discloses an embedded inductor including a coil and a magnetic body covering the coil. The magnetic body includes an insulated magnetic powder, a coupling agent and a resin.
As mentioned above, the embedded inductor and the manufacturing method of the invention utilize a wet process. An insulated magnetic power is coated by a coupling agent and then mixed with a liquid resin. In comparison with the prior art, the surface-processed magnetic powder of the present invention achieves an improved insulation effect. In addition, it can reduce the amount of organic solvent when mixed with the resin, but increases the bonding force with the liquid resin so that the surface of the insulated magnetic powder can be uniformly coated by the liquid resin. This ensures the stability in inductance and performance. The inductor formed by warm pressing or hot pressing is less likely to have cracks. Because of the uniform coat of the liquid resin over the insulated magnetic powder, the output pressure during molding is stable and no high molding pressure is required. This can elongate the lifetime of molding tools.
The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements.
Referring to
In step S02, the insulated magnetic powder is processed with a surface process. The surface process utilizes a coupling agent to coat the insulated magnetic powder. The amount of the coupling agent is about 0.5% to 6% of the magnetic powder in weight. The coupling agent is fully mixed with an organic solvent (e.g., acetone) into a solution A. Then, the insulated magnetic powder is added into the solution A for full mixing, followed by a drying process.
The coupling agent includes, for example but not limited to, a surface modifier or a surfactant. The surface modifier is, for example, organic silyl, titanium-based, aluminum-based or zirconium-based compound. The surfactant is, for example, perfluoroalkyl or lauryldimethylamine oxide.
In step S03, the surface-processed insulated magnetic powder is mixed with a liquid resin. The amount of the liquid resin is 1% to 6% of the magnetic powder in weight. The liquid resin is fully mixed with an organic solvent (e.g., acetone) to form a solution B. Then, the surface-processed insulated magnetic powder is added into the solution B for full mixing, followed by a drying process to obtain a mixture. Besides, an additional step follows step S03. The additional step is to mix the mixture with a lubricant to form a compound magnetic powder. The amount of the lubricant is 0.05% to 1% of the magnetic powder in weight. The lubricant includes, for example but not limited to, stearic acids, wax or graphite. The liquid resin is, for example, a thermosetting resin.
With reference to
With reference to
As shown in
In summary, the embedded inductor and the manufacturing method of the invention utilize a wet process. An insulated magnetic powder is covered by a coupling agent and then mixed with a liquid resin. In comparison with the prior art, the surface-processed magnetic powder of the present invention also achieves the insulation effect. In addition, it can reduce the amount of organic solvent when mixed with the resin, but increases the bonding force with the liquid resin so that the surface of the insulated magnetic powder can be uniformly covered by the liquid resin. This ensures the stability in inductance and performance. The inductor formed by warm pressing or hot pressing is less likely to have cracks. Because of the uniform coverage of the liquid resin over the insulated magnetic powder, the output pressure during molding is stable and no high molding pressure is required. This can elongate the lifetime of molding tools.
Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 096131435 | Aug 2007 | TW | national |
